Hbatf-eesponsive element



1942. w. H. FREYGANG HEAT RESPONSIVE ELEMENT Filed May 22, 1940 INVENTOR f' f i r Hzfigygang BY AZ ORNEY Patented 29, 1942 UNITED sures rs'rs'r Specialties ,velopment ilehl, N. it, a corporation of Corporation, 7 Bloom- New J rsey Application May 22, 1946, fierlal No, 8236,49?

6 Claims.

This invention relates to automatic fire tietectlng apparatus, and more particularly to the heat-responsive elements used in such apparatus.

It is an object of the present invention to provide a heat-responsive element for tire detecting purposes, preferably in the form of a strip or strand of a. material which has reaction charec= teristics exposure, and to mechanical loads which make it superior to other materials used for this purpose.

In devices of this character, heat-responsive elements oi a variety of materials, the form of threads or and it was found that each one of these materials had some property that made it undeslrable for the purpose stated.

The apparatus in question is intended for use on a diversity of hazards standing various operating conditions, such as exposure to continuous high temperatures, meteorologicol and mechanical influences, coupled with the standard requirements of ruggedness and speedy and accurately predictable operation for a given temperature.

In connection with materials employed heretofore, including horsehair, cotton and silk threads, Celluloid, bimetal, and fusible metal, it

was found, that one or more drawbackswere common solvents.

My invention aims to overcome the drawbacks lound in the heretofore known heat-responsive elements by providing an element for the indication of the presence of lire or temperatures eotuvalent thereto, which is made of a synthetic pictorial to be form cl thin strips or filaments.

have found by experiment, including many comparative tests that this synthetic material clmwu into c, strip or filament terms a flre sensielement of a. uniform timeliness and quality,

beings factory produced; that it is practically immune to most reliability due described; and preierably, is in the filaments have been used,

including airplane en pines, and. should therefore be capable of withsolvents; that it will not dc- 5o teriorate over long periods when exposed to inlluences oi weather; that it stands up well under prolonged exposure to high temperatures; and finally that it will fail, very quickly and with reasonable certainty at between 400 and 450 F.

Further, it is easily workable, and therefore is readily applicable to factory production methods.

In consequence of the stable characteristics of these synthetic strands, elements composed of this material hove proven, under numerous tests and actual operating conditions, to be much better suited for the purpose and the conditions set forth above than any other material so for employed therefor.

The material in question, is that popularly known by the trade name nylon. The actual details oi the chemical processes involved in the preparation thereof will not be gone into as they do not form a part oi this invention. t is a commercially available article, the chemical and other characteristics of which have been described ln Letters Patent of the United States, 2,071,250; 2,,ll7i,251;- 2,071,253 and 2,157,116.

The material, in accordance with these Patents is chemically known as a synthetic condensation polymer and may be as synthetic polyemide. This material is obtainable in a number-of shapes and forms, but for fire-detecting purposes is preferably employed as a strand or filament of the approximate thickness of a bristle, the exact size being determined hr the mechanical requirements of the case.

In order to he better able to illustrate the gem erol range of application oi an element oi that untrue, two examples or lire safe-guarding aoparatus have been described incorporating lire sensitive elements of my invention. For a better understanding, reference is not made to the eccompenying drawing, wherein:

Figure i represents, in diagrammatic form. the application of the heat-responsive element to the coverage of an extensive locality, while Figure 2, in a similar manner, indicates a dre detecting device which may be applied locally.

Figure 3 shows an electric alarm circuit employing the device of Figure 2.

There are-s. great many possible cases Where- It may be desired to detect a fire or dangerous temperatures, and each of these may call for a dinerent solution. or the two cases illustrated in the drawing, the apparatus of Figure l coin pl'lses a heat-responsive stronri-lilre element l which is composed of a material in accordance with present invention and be of any, desire; length and fastened. about the spoce to 2 be supervised, S being a supporting wall. The filament is run over pulleys 2, and supports a weight 3 which, when released, through the medium of a connecting link I running over pulley 5, is able to actuate a lever 6 pivoted about a fixed point 6. This lever 1 may perform an? one of a number of functions such as closing an electric alarm circuit, act as a mechanical intermediary for the release of a larger or remotely operating force for the liberation of a fire extinguishing medium, the closing of doors and other fire safe-guarding operations.

The device illustrated in Figure 2, shows a frame 2|, mounted on a housing structure 22 which contains electrical contact elements 23 and 24 adapted to be electrically connected by a ringlike conductor 25 held away from the contact elements by a filament 26. The filament 26, which in function and composition is analogous to the ele-- ment i of Figure 1 is held anchored in the dished portion 21.01 frame 21 and at 28, in the recessed portion of an insulating member 29 which forms a single structure with contact ring 25. Element 28 is held under tension by means of an-expane sion spring 2I0 bearing upon the outer side offrame 2| and on the inner side of member 29.

It is apparent that upon the rupture of the filament 28, contact ring 25 through the force of the spring 2H1 will seat on and electrically bridge the contact elements 23 and 24. These contact elements may be made part of any de sired circuit by proper connection at 2! I and 2E2. The filament may vary in to two inches according to need, the device itself being placed at various points along a circult covering one or more localities. This is shown in Figure 3, illustrative of a representative fire alarm apparatus, wherein 3| is a source of electric current, 32 a conductor leading to an alarm bell 83, and 34 a plurality of return conductors in each of which is placed a circuit closer 35, in accordance with Figure 2.

The operation of the heat-sensitive element in the two applications shown, is self apparent. Temperatures of very nearly between 400 and 450 P. will cause an immediate failure of the heat-responsive the result that such fire safeguarding measures as have been contemplated are initiated immediately upon the attainment of such temperatures.

It is to be understood that the invention, however, does not reside'in any particular applica tion of the heat-sensitive length from about one,

element, but rather in fire saieguarding apparatus having as its flame detecting means an element composed of a synthetic polymer of the class described, as will be apparent from the appended claims.

I claim:

1. In a fire safeguarding system for a hazard involving greatly varying temperatures, vibration and varying climatic conditions. the combination of fire safeguarding means, and means for restraining the operation of said fire safeguarding means including an element of a synthetic polymer of the class described having such length and thickness as ture at its disintegrating temperature.

2. In a fire safeguarding system for a hazard involving greatly varying temperatures, vibration and varying climatic conditions, the combination of fire safeguarding means, and means for restraining the operation of said fire safeguarding means including a filament of a synthetic polymer of the class described.

3. A fire safeguarding apparatus for hazards of the type described, comprising fire safeguardelement, in both instances, with ing operating means, and means restraining said last named means including a fiame detecting element of a synthetic polymer of the class described havlng such length and thickness as to rupture with the desired rapidity at its disintegrating temperature.

4. The combination of fire safeguarding means, operating means for said fire safeguarding means, and means normally restraining said operating means including an element of a synthetic polymer of theclass described having such length and thickness as to rupture with the desired rapidity at its distintegrating temperature.

5. In a fire safeguarding apparatus for hazards of the type described, the combination of fire safeguarding operating means and means restraining said weight from operating including a flame detecting element of a synthetic polymer of the class described having such length and thickness as to rupture with the desired rapidity at its disintegrating tem perature.

6. In a fire safeguarding apparatus for hazards of the type described, the combination of safeguarding operating means including a spring,

and means restraining said spring from operating including a flame detecting element of a synthetic polymer of the class described having such length and thickness as to rupture with the desired rapidity at its disintegrating temperature.

. WALTER H. FREYGANG.

to produce rapid nip-- including a weight, 

